KR20000021571A - Video mute method of tv - Google Patents

Abstract

PURPOSE: A video mute method of a TV is provided to prevent a screen cutting phenomenon, generated when performing the video mute to remove a screen trembling phenomenon, when converting channels or a TV/video mode. CONSTITUTION: A video mute method of a TV comprises the steps of: deciding the input of a TV/video mode conversion key or channel conversion; standing by the input of a vertical synchronization signal from an image signal processor, when the video mode conversion key is inputted; outputting a control signal for performing a video mute in an OSD(On Screen Display) processor and the image signal processor, when the vertical synchronization signal is inputted, performing the video mute, and releasing the video mute after the regular time elapses.

Description

Method for video muting in a television

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video mute method for a television, and in particular, a microprocessor waits for input of a vertical synchronization signal indicating a start (or end) of a new frame during channel switching or television / video mode switching. Is inputted, the present invention relates to a video mute method of a television for performing video muting by outputting control signals to the video signal processing means and the OSD processing means.

Conventionally, the image processing means of the television does not include a video mute function, and a separate mute circuit is added to the outside, so that the contrast and the brightness of the contrast output through the digital / analog conversion unit when the screen is switched. By muting the voltage for a certain period of time, no image output appears on the screen, eliminating annoying conditions.

Korean Patent Laid-Open Publication No. 93-001704 is a television to which the video mute circuit is added.

According to this, the video mute circuit converts contrast and bright and other pulse width modulation data from the microprocessor by the key input of the key input unit into the contrast and bright and other voltages through the digital / analog changing unit and then the image signal processing unit. In a video mute circuit input to a CRT (Cathode Ray Tube), contrast and bright voltage switching for muting the contrast and bright voltages of the digital / analog converter according to the control output of the microprocessor to be input to the image signal processor. It is configured to include a wealth. Here, among the constituent means of the above-mentioned television, the same function as that of the constituent means described in the present invention described later indicates that the names coincide.

The television having the video mute circuit of the above structure turns on the power when the first power-on key is input from the key input unit by the user's operation, and the channel-change data when the channel switch (or the TV / video mode switch) key is input. Outputs to the tuner, and converts the contrast, bright and other pulse width modulation data obtained from the microprocessor into an analog signal in the digital / analog converter and converts the image signal processor The contrast and bright voltage of the digital / analog converter are muted by the contrast and bright voltage switching unit for a predetermined time by the control output of the microprocessor, thereby causing an unobtrusive screen state during the screen switching. Can be removed And so.

That is, the contrast and bright pulse width modulated data is set to "0" by the control of the microprocessor during the screen switching, and when the contrast and bright pulse width modulated data is "0", it is slightly delayed through the digital / analog converter. To compensate for this, the output of the digital / analog converter, that is, the contrast and the bright voltage, is grounded and controlled to eliminate screen shake during channel switching.

On the other hand, in recent years, it is common to configure a video muting function in a video signal processing means without implementing a video muting function by separately adding a video muting circuit as described above.

However, in the case of a television which performs a video mute function by adding a separate video mute circuit, or in the case of a television having a video mute function embedded in the video signal processing means, the video muting is performed by the same method.

In other words, when the microprocessor recognizes both the channel switching or the TV / video mode switching key input from the key input unit, it outputs a control signal so that nothing appears on the screen for a certain period of time. As the scanning is interrupted, the middle part of the screen is temporarily turned black, and the phenomenon that the screen is cut is observed, which has annoying the viewer's eyes.

Accordingly, the present invention seeks to prevent a phenomenon in which the middle of the screen appears to be temporarily cut off due to the video mute performed during channel switching or television / video mode switching.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, which is generated during video muting that is performed to eliminate screen shake during channel switching or television / video mode switching in a television having a video muting function. It is an object of the present invention to provide a video mute method of a television which can prevent screen clipping.

1 is a block diagram of a typical television.

2 is a flowchart illustrating a video muting process of a television according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: key input unit 20: microprocessor

30: tuner unit 40: video signal processing unit

50: OSD unit 60: voice signal processing unit

The video mute method of a television according to the present invention comprises a key input determination step of determining a channel switching or television / video mode switching key input, and a vertical synchronization signal from a video signal processing means when a channel switching or television / video mode switching key is input. Waiting for the input of the vertical synchronization signal waiting for input, and when the vertical synchronization signal is input to the video signal processing means and the OSD processing means to output the video mute control signal for executing video mute, after a certain time to release the video mute It characterized in that it comprises a video mute execution step.

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings by those skilled in the art.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a general television having a video mute function, and includes a key input unit 10, a microprocessor 20, a tuner unit 30, an image signal processing unit 40, an OSD unit 50, and audio. And a signal processor 60.

In the figure, the microprocessor 20 is a preset voltage of a channel selected by the user on the tuner 40 as a means for controlling the overall operation of the television by the key input unit 10 composed of a key matrix of a remote controller or a front panel. The video signal processor 50 and the OSD unit 50 are controlled during channel switching or television / video mode switching to temporarily perform video muting to eliminate screen shaking.

The microprocessor 20 waits for the vertical synchronization signal to be input without executing video muting before the vertical synchronization signal is input from the image signal processing unit 50 even if the channel switching or mode switching key is input from the key input unit 10. When the vertical synchronizing signal is input from the image signal processing unit 50, it outputs a control signal for video muting to the image signal processing unit 50 and controls the OSD unit 50 so as not to output the OSD to execute video muting. do.

The tuner 30 outputs a broadcast signal received by tuning to a channel corresponding to the control of the microprocessor 10 to the image signal processor 40.

Meanwhile, the image signal processor 40 demodulates and detects a broadcast signal applied from the tuner 30, extracts a composite video signal, processes the extracted composite video signal as a displayable signal, and outputs the output signal or not shown in the video mode. It processes and outputs an external input signal applied from the external input terminal, and detects a vertical synchronizing signal and a horizontal synchronizing signal among the signals and outputs it to the microprocessor 20.

In addition, the OSD unit 50 reads a character font corresponding to the control of the microprocessor 10 to generate a character signal using the read character font, and applies the generated character signal from the image signal processor 40. The synthesized video signal is output to a CRT (not shown).

The audio signal processor 60 detects and separates a voice signal from a broadcast signal or an external input signal applied from the video signal processor 40 into a signal that can be output, and then amplifies and outputs it to a speaker (not shown).

A video muting process according to a preferred embodiment of the present invention in a television having a video mute function will be described in detail with reference to the flowchart of FIG. 2.

First, when power is supplied to the television and the power-on key is input from the key input section 10, the microprocessor 20 switches from the standby mode to the activation mode and starts controlling the television.

First, it is determined whether the user inputs a channel switching or television / video mode switching key in the key input unit 10 (S100).

If there is no key input requesting channel switching or television / video mode switching from the key input unit 10, the routine ends without performing video muting, and if there is a request for channel switching or television / video mode switching, the video signal processing unit In operation 40, it is determined whether the vertical synchronization signal is input (S110).

As a result of the determination, if there is no input of the vertical synchronizing signal, the process continues in step S110 to wait for the input of the vertical synchronizing signal, and when the vertical synchronizing signal is input, the process proceeds to the next step to perform video muting (S120).

In the video muting, the microprocessor 20 waits for the vertical synchronizing signal to be input from the image signal processing unit 40, and when the vertical synchronizing signal is input, the control signal for video muting is input to the image signal processing unit 40 and the OSD unit 50. This is done by outputting to and temporarily erasing the screen.

The reason for performing video muting by waiting for the vertical synchronization signal to be input during channel switching or television / video mode switching is that the channel muting time is matched with the start of (or ending) the new frame. If the video mute is executed immediately when there is a request for switching or television / video mode switching, the video mute is executed while the syringe is in between, and the middle of the screen is turned black to prevent the screen from appearing to be cut off.

Subsequently, after executing a video mute and waiting for a predetermined time to elapse, after a predetermined time has elapsed, the microprocessor 20 outputs a control signal for canceling video mute to the image signal processor 40 and the OSD unit 50. The video mute is terminated in order to remove the screen shake and prevent the screen from being cut off at the same time during the channel switching or the TV / video mode switching (S130 and S140).

As described above, according to the present invention, the microprocessor recognizes the channel switching or the television / video mode switching in executing the video mute operation used to prevent the shaking of the screen during the channel switching or the television / video mode switching. In one case, instead of executing video mute immediately, wait for the input of the vertical sync signal indicating the start (or end) of a new frame, and then execute the video mute when the vertical sync signal is input. Regardless of whether or not a new frame is started, video muting is performed during the scanning period, thereby preventing the scanning from being cut off in the middle of the scanning.

While the invention has been shown and described with respect to particular embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention as set forth in the claims. Anyone can see it easily.

Claims (1)

In a television with a video mute function, A key input determination step of determining a channel switching or television / video mode switching key input; Waiting for inputting a vertical synchronization signal from the video signal processing means when the channel switching or television / video mode switching key is input; And a video muting step of outputting a control signal for executing video muting to the video signal processing means and the OSD processing means when the vertical synchronization signal is input, and executing the video muting, and releasing the video muting after a predetermined time. Video mute method of television.